Skewness and critical current behavior in a graphene Josephson junction

In this work, the DC Josephson effect is investigated for a superconductor-graphene-superconductor junction in both short- A nd long-junction regimes. The electric transport properties are calculated while taking into account the contribution of the discrete and continuous energy spectrum. In our ap...

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Autores:
Manjarrés, Diego
Gómez Páez, Shirley
Herrera, William J.
Tipo de recurso:
Fecha de publicación:
2020
Institución:
Universidad El Bosque
Repositorio:
Repositorio U. El Bosque
Idioma:
eng
OAI Identifier:
oai:repositorio.unbosque.edu.co:20.500.12495/2033
Acceso en línea:
http://hdl.handle.net/20.500.12495/2033
https://doi.org/10.1103/PhysRevB.101.064503
Palabra clave:
Differential equations
Critical current density
Insulators
Josephson effect
Graphene
Green's function methods
Grafeno
Hidrocarburos aromáticos policíclicos
Conductores eléctricos
Rights
License
Acceso cerrado
Description
Summary:In this work, the DC Josephson effect is investigated for a superconductor-graphene-superconductor junction in both short- A nd long-junction regimes. The electric transport properties are calculated while taking into account the contribution of the discrete and continuous energy spectrum. In our approach, the phase dependence of the critical current is calculated at arbitrary temperature and doping level, which generalizes previous results. We show that critical current Ic and skewness S exhibit critical points as a function of graphene doping EF, which can be explained by Klein resonances in graphene. We give a general characterization of S vs Ic curves while fixing temperature or doping level. When the temperature dependence of Ic is analyzed, we find differences with respect to conventional Josephson junctions, given that there is a relevant doping effect. In the long-junction regime with EF far away from the Dirac point, the Ic vs T curve may exhibit an exponential decay law, which has been measured recently. We report the temperature dependence of S in the whole range of temperature, and our approach allows us to account for skewness suppression in the vicinity of the Dirac point, which is in agreement with recent experiments. We mention some effects which can be attained in Josephson junctions with well-defined edges and for transparency values below unity of the graphene-superconductor interfaces.